Measured service telephone system



Dec. 28, 1937. K, WOLLACK 2,103,441

MEASURED SERVICE TELEPHONE SYSTEM Filed Sept. 26, 1955 lOe I NS p a 5 w- N o J or a F J 9 H l- H ul '5 I I v- U I (9 v INVENTOR E KURT WOLLACK ATTORNEY.

Patented Dec. 2a, 1937 gleam PATE MEASURED snnvrcn TELEPHONE SYSTEM Kurt Wcllack, Berlin,

Siemens & Halske Germany, assignor to Aktiengeseilschait, Weirnerwerk Siemensstadt, near Berlin, Germany Application September'ZG, 1935, Serial No. 42,239

r In Germany October 2, 1934 9 Claims.

The present invention relates to a circuit arrangement for metering variously rated calls in remote communication systems, more particularly in telephone systems.

In such systems it is a well known practice to effect the metering operation after the completion of a call. This method has several advantages. For example, it is possible in particular cases, suchas the breaking down of a low rated call in favour of one more expensive, to suppress the metering. Furthermore, if only the speaking leads are available for the transmission of the metering impulses, it avoids the necessity for providing special balancing devices dependent upon the device receiving the metering impulses, which if the metering impulses are to be transmitted duringthe call have to be attached perm-anently to one of the speaking leads.

If, however, a highly rated call is set up for which an impulse train consisting of a large number of metering impulses has to be transmitted after the completion of the call, it may not be practical to transmit the metering impulses only at the close of the call since, especially in times of heavy trafiic, the withdrawal or release of the connecting devices and switches and use of the line until the end of the metering may be very disadvantageous to the operation of the system.

The object of the invention is to enable the metering of highly rated calls to take place during the existence of the call while obviating the necessity for providing special balancing devices in the line, and this is accomplished by providing two switching paths for the metering impulses, in one of which switching means occur which only connect up the device'for receiving the metering impulse at the moment for eiiecting the metering, while the other path contains a device (glow lamp) which does not disturb the symmetry of the speaking lines, over which device a metering impulse receiving device is permanently connected to the metering lead (speaking lead).

The present invention may be applied with considerable advantage to large telephone systems selector VW, a first group selector IGW and other connecting devices of which those subsequent to the first group'selector are only partially represented.

In Fig. 2 another first group selector is shown as a second embodiment. The preselector and the devices subsequent to the group selector are identical with those of Fig. 1 and are therefore omitted.

When subscriber Tn, Fig. 1, removes his receiver in'order to set up a call, the following circuit is set up for relay R: earth, winding of relay R, contact 2t, subscribers loop, contact 315, resistance Wil, battery, earth. At contact 'lr relay R completes the operating circuit for rotary magnet D of preselector VW: earth, battery, contacts 11",

fit, rotary magnet D, relay interrupter RU, earth. Under the influence of the relay interrupter the wipers w, b, c, d, of the preselector are stepped round until they find a free first group selector" IGW. The following testing circuit isthen'set up over wiper c: earth, battery, contact 8r, windings II and I of relay T, wiper c of preselector VW, resistance Wz'Z, contact 20?), off normal contact 2 l R: (opened after the first vertical step of the group selector), windings II of relays A and B, earth. In this circuit relay T of the preselector energizes (the meter Z in parallel with winding I of relay T does not energize), as do also relays A and B'in the first group selector. The opening of contact 6t breaks the advancing circuit for rotary magnet D of the preselector so that this switch is brought to rest. By the closing of contact St the high resistance winding II of relay 'I' is short-circuited, thus preventing a double seizure of the free group selector which has been reached. By the opening of contacts 2t and St the circuit for the line relay R is broken and the speaking leads are switched through to the subsequent group selector IGW by the closing of contacts it and it. The feeding of talking currentv to the calling subscriber Tn then takes place over windings I of relays A and B in the following,

circuit: earth, contact 9a; winding I of relay B, wiper b of preselector VW, contact 4t, Subscribers loop, contact it, wiper a of the preselector, winding I of relay A, battery, earth. Afterthe release of relay R and the opening of contacts 11* and 81', thehigh resistance winding II of relay T is disconnected, and the guarding circuit follows the following path: earth, battery, restoring wiper d of preselector VW in the working position, cont-act t, winding I of relay T- (and in parallel the winding of the meter Z, although thelatter cannot energize in this circuit), and over wiper c to the group selector IGW.

In the group selector relays A and B have been energized. By the opening of contact 20b relay C has its short circuit removed so that it is brought into the circuit set out above, and energizes. By the closing of contact 220 a locking circuit is established for relay C over resistance Wi3.

The setting of the group selector IGW takes place in the Well known manner. Accordingly the switching elements necessary for setting the selector, such as the vertical and rotary magnets, and the controlling means appertaining thereto, etc., are not shown in Fig. 1.

It will now be assumed that subscriber Tn sets up a local call within the same exchange, 'or a call for which the meter Z of the calling station is advanced only once.

When the wipers of the group selector IGW have been raised to a particular level by the first impulse train and have automatically sought out a subsequent free connecting device for example a final selector LW, the following testing circuit is set up: earth, contact 260, winding II of relay P, winding I of relay P whose short-circuit is removed at contact 250, wiper c of the first group selector, winding of relay CI in the final selector, battery, earth. In this circuit relay P of the first group selector and relay CI of the final selector both energize. By the closing of contact 24p the high resistance winding II of relay P is disconnected and thus the subsequent connecting device that has been taken into use is protected against further seizure. At contacts ltp and tip the speaking leads are switched through to the subsequent connecting device. The subscriber now dials the second and third digits of the desired number and thereby sets the final selector LW in the well known way on the called line. This is represented in the drawing only in so far as it is necessary for an understanding of the invention.

When the desired subscriber replies the final selector LW moves into speaking position'by the controlling switch being brought to position 8, in which contact S8 is closed. The winding of relay Q which is connected to earth is thereby connected to the upper speaking lead.

When, at the end of the conversation, subscriber Tn replaces his receiver, relays A and B in the first group selector release. By the closing of contact 20b the winding of relay C is short-circuited so that this relay deenergizes shortly afterwards. By the opening of contact I50 the lower speaking lead in the first group selector is disconnected, while the closing of contact Me connects the metering relay ZI to the lower speaking lead. The following circuit is set up by the closing of contact 290: earth, battery, winding III of relay P, contacts 290, I610, wiper a of the group select-or, control switch contact S3, winding of relay Q, earth. Relay Q in the final selector energizes in this circuit, and relay P in the group selector holds up although its winding I has been short circuited by contact 250. A premature release of the group selector is thus prevented. By the closing of contact Hg in the final selector the following circuit is set up: earth, battery, resistance W25, contact 21q, wiper b of the first group selector, contacts Hp, 14c, winding of local call relay Zl, earth. Inthis circuit relay 2! energizesand operates its contact lBzl. Resistances Wz'Z and Wz'3 are thereby short circuited (contact 1220 does not open before contact l8zl has closed) and the current over the testing lead of the preselector is thus increased and causes the advancement of the meter Z of the calling subscriber Tn. The local call metering relay Zl closes its contact 28a! thus short circuiting winding III of relay P which thereupon releases and initiates the release in the known way.

If the called subscriber replaces his receiver before the calling subscriber the controlling switch of the final selector is moved to position 9. In this case no energizing of relay Q in the final selector takes place. Instead the control switch contact S9 is closed and this immediately connects battery for metering to the lower speaking lead. After the replacement of the receiver at the calling station and the release of relay C the metering relay Zl is energized and brings about the metering and the release as described above.

The case will now be considered in which the calling subscriber sets up a highly rated or toll call. The setting of the preselector takes place in the manner already described. The group selector IGW is now raised to a level to which a connecting toll line VL leading to another exchange, for example the main exchange, is connected. The testing circuit then passes over resistance Wid instead of relay Cl Only those individual parts of the connecting device reached over the connecting line which are necessary for the explanation of the invention, are shown.

These comprise a contact 481: which is closed during the transmission of a metering impulse train, and a contact 412] which connects the lower speaking lead over a resistance Wi6 to a powerful battery for striking the glow lamp. This contact 4121 is under the influence of a meter advancing device which on the commencement of the conversation and then after a time interval of definite duration closes and opens the contact 472i a different number of times according to the selected call direction. In this way metering impulse trains, whose length is defined by the cost of the call, are transmitted by the meter advancing device (not shown) to the lower speaking lead at definite time intervals. On the transmission of a metering impulse train by the meter advancing device the toll call relay Z2 is energized intermittently in the following circuit: earth, striking battery for the glow lamp, resistance Wifi, contact 412), lower speaking lead, wiper b of the first group selector, contacts Hp, I50,

glow lamp GI, metering relay Z2, earth. Metering relay Z2 thus closes its contact I 922 several times thereby increasing the current over the testing lead of the preselector and thus advancing the meter of the calling subscriber corresponding to the influencing of the metering relay Z2.

In addition the toll call metering relay Z2 closes its contact 2322 intermittently thus establishing the following circuit for the delayed release relay E which keeps its contacts in the working position during the brief current interruptions: earth, contact 2322, winding of relay E, battery, earth. Relay E opens its contacts Hie and its thus breaking the speaking leads, and closes contacts I! e and l2e whereby a buzzer signal is connected up which indicates to the calling subscriber that the metering is occurring at this moment. Dur

ing this time, which, of course, is very brief, perhaps one-half. to one second conversation cannot be heard. When the particular number of impulses have been transmitted contact 2322 is opened for a longer time and relay E deenergizes. The speaking leads are switched through again and conversation can commence or can be dis- 7 5 tinued- Du in the. transm ssioniof the bu zer:

signal the subscriber can, by quickly, hanging up catingthe metering operation, switching means can be provided in the meter advancing device which sends out a notification signal over the speaking lines some time before the transmission of the metering impulses for example ten seconds previously. The calling subscriber can then bring his conversation to an end quickly within the ten second period still remaining.

If the subscriber Tn replaces the receiver during the transmission of a' metering impulse train either by chance or because he hears the signal indicating the occurrence of the metering operation, the -whole of the impulse train is nevertheless transmitted as before. 'Thus if relay C deenergizes during the transmission of the metering impulses while onlya part of the metering impulse train has been transmitted to metering relay Z2 over the glow lamp, the remaining impulses are taken up by the metering relay Zl, this occurring in the following circuit: earth, winding of metering relay Zl, contacts Mo, lip, wiper b of the first group selector, connecting line VL, contact 412], resistance Wit, high tension battery, earth. The impulses, therefor-e, which are prevented from operating the meter of the group selector, contacts. I610, 290, winding III of relay P, battery. earth. The release of the connection is only in tiated by the release of relay when contact 58a: is opened after the last metering impulse.

' According to the embodiment described above two additional relays are used in the normal group selector for eiiecting the metering operation, namely, the second metering relay Z2 and relay E; In Fig. 2 the first group selector is of such a kind that the use of special relays is unnecessary; The devices'preceding and following the group selectorare not shown since they correspond to those of testing lead of the first group ,selector corresponds to that of Fig. land is therefore not shown.

When the subscribers connection has been set up asfar as the group selector, Fig. 2, relays A and B energize over their windings II in the same wayas described above. By the opening of contact 20b relay C is energized and locks up by closing contact 22c. .When the first digit is dialed relay A is intermittently deenergized. Contact 39a isaccordingly closed corresponding to the impulses received and the following circuit is set.

up for the vertical magnet H! of the first group selector: earth, contacts 380, 39a, windingII-of relay V, contacts dfidl, rotary off normal contact 42w opened after the first rotary step of the group selector, vertical magnet Hi battery, earth. The

vertical magnet thus. raises the group selector to a In the same way the,

that it: possesses a definite delayed release prop erty and holds up its contacts during the interruption of the circuit at contact 39a. At the end of the impulse train, after the prolonged opening of contact 39a relay V deenergizes and closes its contact 3617. The rotary magnet DI is thereby operated and closes its contact Mr. At this contact the following circuit is established for a winding I of relay V: earth, contact l ldi, winding I of relay V, vertical magnet HI, battery, earth; The vertical magnet cannot energize in this circuit. Relay V opens its contact 3% and. thus breaks the circuit for the rotary magnet. Thisby closing contact Md! causes relay V to deenergize again. This reciprocal play between the rotary magnet and relay V continues until the group selectorhas found a subsequent free connecting device. Thereupon the testing relay, which is not shown, energizes and by opening its contact 37;!) brings the group selector to rest. The closing of contacts Hip and lip causes the switching through of the speaking leads to the next connecting device.

By the transmission of further impulse trains the subscriber establishes the connection to the desired subscriber. If the call is a local one battery potential is connected over resistance Wi5 to the lower speaking lead on the termination of thecall in the same Way as in the arrangement according to Fig. l, whereupon the metering relay Z3, which is connected over contact 330 to the lower speaking lead, is energized in the following circuit: earth, winding of relay Z3, contacts'ttc, Hp, wiper b of the first group selectoig contact, Z'lq or control switch contact S8, resistance Wi5, battery, earth. By the closing of contact 3423' and the disconnection of resistance WiZ thereby produced, the increase in current strength over the testing lead of the preselector which is necessary for advancing the meter once, is brought about.

The release of the group selector is again initiated by a contact of the metering relay, namely contact 3023, which short circuits winding III of relay P. j V

If the subscriber sets up a more'highly rated call metering impulse trains of striking potential are .transmitted 'at definite intervals over. the lower speaking lead during the existence of the call. The metering relay Z3 in the first group contact M23, windings II and I of relay V, vertical magnet HI (which cannot energize in this circuit), battery, earth. Relay V closes its contact tev and thereby completes the. short circuit for its winding II which was prepared by contact 45p. Relay V is thus made slow to release, this feature being adjusted so that it holds up its contacts during the brief interruptions at contact H23. 'Relay V thus opens contacts 3h) and 322; during each transmission of a metering impulse train and thereby disconnects the speaking,

leads leading to the calling subscriber in order to protect the subscriber from objectionable crackling noises produced by the impulses. A signal which indicates to the subscriber the occurrence of the metering is not represented in Fig. 2 but can, of course, be provided in the same way as in the arrangement according to Fig. 1.

If the subscriber replaces his receiver during the transmission of an impulse train, the glow lamp is short-circuited by the release of relay C and the closing of contact 330. The impulses which at this moment still remain to be transmitted, pass, over contact 330, to relay Z3, so that the transmission of the metering impulse train is not disturbed by the clearing signal for the calling subscriber.

What is claimed is:

1. In a measured service telephone system, a calling subscribers line, means including a group selector for setting up a connection from said line to a called line, a metering relay and a glow lamp connected in series to a talking conductor at the said group selector, said glow lamp normally maintaining said relay open, means beyond the group selector for transmitting high voltage impulses back to the group selector through a talking wiper thereof to break down said glow lamp and operate said metering relay, and a meter for the calling line controlled by said metering relay.

2. In a measured service telephone system, a calling subscribers line, means including automatic switches for setting up a local connection or a toll connection from said line, a meter for the calling line, local and toll meter control circuits including a talking conductor, means effective over said local meter control circuit in the case of a local connection for operating said meter responsive to the release of the connection, means efiective over said toll meter control circuit in the case of a toll connection for operating said meter before the connection is released, and means for preventing unbalance of the talking circuit during either a local or a toll connection, said last means including a glow lamp connected in said toll meter circuit to said line conductor for maintaining said toll meter control circuit open during conversation and including means for maintaining said local meter control circuit open during conversation.

3. In a measured service telephone system, a

calling subscribers line, means including an automatic switch for setting up a local or toll connection from said line, local and toll meter control circuits each including a talking Wiper of said switch, a meter for the calling line controlled over said circuits, means including relay contacts for maintaining the local meter control circuit open during conversation, and a glow lamp for maintaining the toll meter control circuit open during conversation.

4. In a measured service telephone system, means including automatic switches for setting up connections from a calling line to called lines, a meter for the calling line, a meter control relay, a glow lamp, means for operating said relay in series with said glow lamp to charge for one connection, and means for operating said relay over a circuit excluding said lamp to charge for another connection.

5. In a measured service telephone system, means including automatic switches for setting up connections from a calling line to called lines, a meter control circuit including one talking conductor and a glow lamp, another meter control circuit including said talking conductor but excluding said lamp, and a meter for the calling line controlled over one circuit to charge for one connection and over the other circuit to charge for another connection, said glow lamp non-conductive during said other connection and conductive only in said one connection for rendering said first meter control circuit effective.

6. In a measured service telephone system, a calling subscribers line, means including automatic switches for setting up a connection to a called line, a meter for the calling line, a metering relay adapted to control said meter while the connection is established, and a second metering relay adapted to take over and complete the control of the meter if the calling subscriber hangs up while the said first metering relay is operating.

7. In a measured service telephone system, means including an automatic switch for setting up connections from a calling line to called lines, a meter for the calling line, a meter control circuit including a talking conductor of an established connection, means for transmitting a series of metering impulses over said circuit to operate said meter, and a second meter control circuit substituted for the first upon release and effective to receive the remaining impulses of a series and to control said meter in accordance therewith in case the release is initiated while such series is being transmitted.

8. In a measured service telephone system, means including an automatic switch for setting up connections from a calling line to called lines, means for transmitting high or low voltage metering impulses back through a talking conductor of said switch depending upon the type of connection set up, a meter control relay permanently connected to said talking conductor in series with a glow lamp for receiving high voltage impulses, a meter control relay temporarily connected to said talking conductor upon the release of a connection to receive a low voltage impulse, and a meter for the calling line controlled by one or the other of said relays, said glow lamp only rendered conductive in response to high voltage metering impulses for controlling said first meter control relay.

9. In a measured service telephone system, a calling subscribers line, means including a group selector and a final selector for extending a connection from said line to another line, means controlled over one talking conductor extending between said selectors for temporarily holding the connection after the calling subscriber has hung up, a metering relay in the group selector controlled over the other talking conductor from the final selector, and a meter for the calling line operated by said relay.

KURT WOLLACK. 

